Tool



A. THOMAS Feb. 15, 1949.

TOOL

Filed Oct. 15, 1945 MN m 5 V M s r gm 1 F INVENTOR.

BY zr Patented Feb. 15, 1949 STATES TOOL Albert Thomas, Munhall, Pa. Application October 15, 1945, Serial No. 622,309

1 Claim. 1

This invention relates to boring tools constructed for adjustment to provide a range of boring diameters with one composite tool member, and more particularly to such a composite tool construction in which extremely accurate variations of boring diameter may be readily attained.

One of the principal objects of the invention is to provide a precision boring tool construction which has simple and easily operated means for efiecting accurate precision adjustment of the tool carrying member and for maintaining said adjustment for accurate precision work at a predetermined work setting.

Another object' is to provide such a construction in which extremely accurate work positions may be readily attained by easily efi'e-cted relative rotation of the two parts of the composite construction and those parts efiectively locked and maintained in any selected positioning by means of mere axial movement of one part into another.

Another object of the invention is to provide a boring tool having cooperating tapered interfitting parts constructed for ready angular adjust ment to effect extremely accurate relative lateral settings, said parts being also constructed for ready axial movement while in maintained lateral setting to effect strong locking engagement of said parts in work position.

Another object is to provide a boring tool in the form of a shank member and a tool member removably joined together for accurate lateral adjustment within a predetermined range by relative angular movement of a long tapered tool bearing part within a correspondingly tapered receiving socket in a tool holder and for simple and effective locking of the parts in undisturbed adjusted setting by simple axial movement only of the long tapered tool bearing part within its receiving socket.

Other objects and advantages will be apparent from the following description, the accompanying drawings and the appended claim.

In the drawing, in which like characters of reference designate like parts throughout,

Fig. 1 is a side elevation, partly broken away, showing a composite tool construction embodying the invention;

Fig. 2 is a section taken substantially on a vertical plane including theline 22 of Fig. 1 g

and perpendicularto the showing of Fig. 1, and showing the tool carrying member turned to the position of maximum lateral adjustment;

Fig. 3 is a section taken substantially on the line 3-3 of Fig. 1; and

Fig. 4 is a section similar to Fig. 3 but showing the tool member rotated through from the position shown in Fig. 3.

In the drawings, in which a preferred embodiment of the invention is shown, shank or tool receiving and holding member Hi has one end I I formed for driving connection in a spindle or chuck device of a drill press, boring machine, or similar machine tool. At its opposite end shank member I!) is provided with a conical bore or receiving socket l2 which is of considerable axial length to provide a long bearing surface. similar long tapered conical extension or insert boss portion M is formed at one end of the other main tool member I5. At its opposite end, tool member 15 is provided with a cutting element or bit it held in work or boring setting by means of one or more looking or set screws, one set screw is being illustrated as suflicient for a device of approximately the size shown. The base of boss portion I4 is of reduced diameter with respect to flange portion 20 of tool member l5, the flange portion thus extending outwardly beyond the extension M, this portion 29 thus forming an enlargement which serves for ellecting angular movement of the boss in the receiving socket l2. The face 22 of this enlargement is arranged generally transverse to the longitudinal axis of the. tool carrying part l5 and said base or boss por-' tion It is also somewhat larger in diameter than the maximum diameter of conical bore lit. The shoulder 22 will thus, at all times in adjustment and work setting of the device, be maintained in spaced relation with the adjacent and complementary end face 23 on portion 24 of shank member I0, this spacing being indicated by the numeral 25.

Bore l2 and boss M are substantially complementary and are machined so that they will be held in tight frictional engagement when in adjusted work setting. For extremely accurate precision work the cooperating surfaces of the receiving bore l2 and the extension M are accurately machined so that the parts will fit together throughout a long bearing contact with such snugness and close engagement that the longitudinal axes of the parts 10 and I5 are parallel, or substantially so, within the predetermined range of allowabletolerance in the accuracy of boring required; and, also, so that they are maintained in such engagement that they are held together with great rigidity. Boss I4 is cut away to provide walls 26 and 28 of an annular recess or groove 30-which is V shaped in crosssection and is spaced from the end and base of the boss. In Figs. 1 and 2 the cut out portions 28 and 28 are in the form of frustums of cones, and may he formed by simple machining operation so that their smaller ends come together at the apex of the V shaped groove and this construction may be readily and cheaply machined to desired accuracy for finest precision work by a simple turning operation, with the sides of the groove forming an angle of substantially 90. As shown, shank member ii! is machined or formed to provide an enlarged portion 31, thus providing adequate strength in the zone of the receiving bore 12, with reduced weight. This enlarged portion is chamiered or beveled as at 32. This enlargement 3| carries a passage 33 arranged at an acute angle to the axisofsliank Hi and receives a locking pine i one end-of which bears against the face 28 and is adjustable toward and from such face. fhis Pin is constructed so that it exerts a pressure on face 28 theu'esultant of which :tends to move the part l 3 axially in the bore 12 wither-li any substantial or objectionable tendency towards annular movement or tilting which would disturb the selected relative angular :positioni-ng "of parts iii} and iii. Two 10f these axial adjustment locking pins are shown, and the-enlargement 32 is provided with two bores or passages ."fdr r ceivingthe pins, the outer end of :each passage being threaded and -.cpening through the inclined or chamfered portion The passages for receiving these pins are shown as :having their axes lying in a plane which-includes the longitudinal axis of the extension M, and inclined at such an angle to said axis as -to-clear theface 32 and extend into the groove to :rest against the face 28 so that when urged :against said face 28 the resultant force effective upon the extension or insert portion a l will lae exerted to iurgesaid extension i4 forxstraight :line axial movement, coaxial with the longitudinal axis of :the shank member it and here 42,:whereby anytendency toward eifecting angular mcvement or tilting of the extension it within its :receiving bore +2 is avoided, and the long bearing taperedwooperating surfaces of the extension Hi and member 1 2 are thus urged into acct-irate contacting relationship to provide a long hearing support fcrthe two parts in coaxial relationship. By meanszcf this construction the two -'main parts of the composite tool may be so constructed that theyimay he readily and simply manufactured to effectuate and maintain extremelyaccurateadjustment without"difhcultand costly manufacturingoperations:and without the necessity :of ipriovidin g :additicnal cooperating parts :requiringfgreat "nicety and precision in the manufacturing of the several relatively cooperatingipartsgand without the necessity of providing different parts upon each main portion of the composite tool which :must be formed with extreme relative precision for conjoint adjustment to secure variable work settings and which must be -maintained zjcintly in extremely excm'ate relati-ve adjustedposition'under working-loads.

By arranging "the pin receiving bores so that the axes of theipins will be substantially normal to the'cooperating face :28 of boss 14, the more a-Xial adjustment of one main part 0f the -composite'tool'with respect to 'the other without any material or objectionable tendency toward causing angular cr tiltin'g m'ovement of the extension M with respect to the member in is avoided, and

thus a very simple, cheaply manufactured, ac-

curate and highly eflicilit and effective means is pi GVi'dc-id wirereby u on backingcff of the pins 4 34 the extension is may be readily moved angularly in its receiving bore 12, and by forcing the pins 3 3 inwardly to thus exert pressure contact upon the face 23 a simple axial movement results which locks the two main parts of the tool in the desired angularly adjusted position, and through the contacting long bearing surfaces provides a very rigid assembly which readily withstands working operations and maintains the tool within the, predetermined allowable tolerance range in operation, such as a boring operation. The outer parts of the pins 34 are shown as threaded to engage in the threaded portion of the pin receiving passages and they are provided at their outer ends with means for receiving a tool to manipulate them, so that they may be screwed :down :to effect the desired tight fit between the surfaces of the extension i4 and of receiving bore 12. As is shown clearly in Figs. 3 and l each of these pins is provided with an hexag'onal recess 35, to receive-thecorrespondingly shaped tool, as -a convenient we'll blmown construction for" enacting in :or out movement of thepins. V

Whil'e i1hebore 4 2 is axially parallel to the axis or the shank member 1c, the axis or this bore is coincident with the axis of portion 24 of shank member i 5 but eccentric with respect to the :axis of the main portion-of the shankmember. TLhi-s is shown particulamlylin Fig52 anddn Figs. 3 'and 4 in which the eccentricity 'is considerably exaggera ted for purposes of {clearer illustration. The axis of the shank member m is indicated-at 3B and the axis or the bore if2ahd shank portion ld at 38. Likewise, boss portion :4 and fiange portion 2d are concentric with respect to each other, and theiraxis is i parallel to the main axis Ml of the tool member f5 but eccentric with respect thereto, and as this-eccentric axis of these portions I 4 and '20 in "all angular settings coincides with the axis 380? the bore l-Zgthedotted line :38 serves to .indicate the positioning of both these eccentric axes. Because :or this eccentricity of the axes of *the bore l 2 and the extension l Leach with'respe'ct to th'e'mainaxesfidand d0 respectivly, angular adjustment of the extension l4 within theb'ore m willresult in lateral adjustment of the main axis i0 With respectto'the axis 36; and if the eccentricityof e'ach is'made equal, then by meansof such angular adjustment the lateral setting of 'the tool carrying member 15 may be varied with respect to the main axis 3fi by'a variation ranging from zero "to the -maximum lateral adjustmentwhich will be the sum of the eccentr icities. ln this way hy simple angular adjust-- ment through 180 are, the lateral setting of the tool carrying member :[5 may be varied within the predetermined range idf adjustment, to provide a very simplefruggedand extremelyaccurate tool which may be utilized in lieu of 'a substantial number of diiferent sized tools, the angular setting eflecting extremely accurate variations in the working cliameter of the tool carr-ying mem: ber for diite'rentidianreter 'boringreparation. The dimensions of the cooperating conical surfaces of the "extension M 'and the Ereceiving bore "12 are such "that the cooperating :surfa'c'es thereof 'are brought into locking engagement before'the face 22 engages'into the opposingfend of the part2 As shown theehd of the extension M termin'ate's short (if the bottom ofthebase sotthattlie desired result-may not be prevented.

Figs. 2 and 3 illustratethe deviceln theposition offmaximum eccentricity between tool' member :I 5 and shank member ID, withiaxis' 38 aofiset with respect to axis 35"and 40similarly offset with respect toaxls 38, although it should be understood that in the drawings the relative offset. between said axis. is exaggerated for purposes of illustration to an extent much greater than would customarily be employed ln thisposition, cutting element 16 on tool [5, for a given bit setting, will bore a'hole of maximum diameter. If it is desired to reduce the size of the hole bored by cutter IE, it is merely'necessary to release screws 34 and rotate boss l4 in bore I2. If the degree of eccentricity between the two sets of axes is the same, then when tool member I5 is rotated through 180 from the position shown inFigs. 2 and 3, it will be substantially concentric with shaft member as indicated in Fig. 4. In other words, by rotating tool member l through 180 from the position shown in Fig. 4 to the position shown in Fig. ,3, it is possible to increase the diameter of the hole bored by cutter l 6 to an extent equal to the sum of the offset between axes 3B and 38 and the oifset between axes 38 and 40. The scale means shown in Fig. 1 provides for accurately determining the adjustment or setting of the bit carrying part [5, and the diameter of the hole bored by the cutter l6. As shown such scale means 42 is carried by flange 20 on tool member l5 and adapted to register with a suitable index mark 44 adjacent end 24 of shank member I 0. Furthermore, since the scale and basic index point are on portions 20 and 24 which are cylindrical, coaxial and of substantially the same diameter, and since they are separated by a relatively short distance, the relative setting of these parts may readily be accomplished as the adjusted scale may be easily read with great accuracy in all positions of adjustment. Since Fig. 1 shows the tool in the position of maximum eccentricity, the maximum value of scale 42 is shown in register with index mark 44, and the zero point of scale 42 will accordingly be positioned at 180 from said maximum value. The knurled portion 45 is formed integral with tool member [5 and facilitates easy manipulation to efi'ect desired relative rotation between boss l4 and bore l2 to adjust the tool to predetermined setting. And since there will be no disturbing angularly efiective, tilting or buckling forces as the axial locking motion is caused, this knurled portion may be readily maintained in precise adjusted position while the locking motion is effected.

ter element 16 to be varied to cut to diametersand with extremely finev varying up to, 0.0125? lateral adjustments for easily observed angular movements of the scale. .Furthermore, since as pointed out the relative angular setting of the The construction of this invention permits of I attaining read and extremely accurate adjustment, within the predetermined range, and of assuring that this adjustment will be undisturbed during locking and also maintained under working forces. And this is accomplished by the use of only two main tool parts and the simple and effective locking and position maintaining means. Thus this small number of component parts gives great accuracy and ease of adjustment with easily and simply manufactured parts, which parts do not require finishing to an extent necessarily comparable with the accuracy of the composite tool in use, but it is sufficient if the cooperating long bearing surfaces may be locked in positioning to insure strong frictional engagement therebetween for the maintained setting desired.

Very satisfactory results, for quite accurate adjustments and operations have been secured in practice with this construction where the tool member I5 is approximately 1%" in diameter and the shank and tool members are constructed with the eccentricity represented by each of the tool and shank members either before or during tightening of thelocking screws will notbe subjectedto disturbing angularly directed forces and since as. shown the graduations of the scale are, quite substantially separatedfrom each other, even when measuring to so line a unit as 0.0005", under normal usage the adjustment will be ac curate to tolerances of a fraction of that amount.

The boring range of the tool may be varied also by adjustment of the cutter element with respect to the tool member I 5. Its boring diameter, for the tool member referred to, may very satisfactorily range from approximately to For a fixed setting of the cutter element its lateral adjustment and the size of its boring diameter can be controlled very accurately by the relative rotation of the boss on the tool member in the complementary socket in the shank member, as described. Another size of tool found satisfactory for larger diameters uses a tool member diameter of approximately 1", and with such size for the member l5 the tool element may be satisfactorily adjusted for a boring range of approximately from 11%" to 2", with the same accuracy of adjustment for each setting of the cutter element and without alteration or modification of the shank element. Other tool members of difierent diameters and lengths may be similarly utilized for other boring ranges and depths and similarly without modification of the shank member, which need only be of sufiicient diameter over the major portion of its length to withstand the torque and bending forces applied thereto in use. The accuracy of lateral adjustment by the eccentricities may be made more or less than that resulting in the devices described using the above noted 0.00625", by varying the actual and relative eccentricities to increase or decrease the accuracy of adjustment and also the permissible amplitude of lateral adjustment.

While the form of apparatus herein described constitutes a preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise form of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claim,

What is claimed is:

An adjustable boring bar comprising a shank member adapted at one end for attachment to a spindle and having at its other end a substantially conical, elongated bore axially offset with respect to but having its'axis parallel with the axis of said shank member, and opposed symmetrically arranged, tapped bores intersecting said conical bore in a common annular plane; a tool supporting shank adapted at one end to receivea cutter bit and having at its other end a substantially conical, elongated boss axially oifset with respect to but having its axis parallel shape'd igroove andia:dkptdiwhenfilddsenectftmsek 1 cure saidishanlfi membeivand said tool. snpnoztmgi shamagainst axiaridislocatiom whilwpermittingr relative rotational movement" to sweet" adjust menu of? saidrf cutt'en bit shank" ra'di'akly off said?- shank memtier -to overcome objectionable: eccen trffirmt'atibnof trietoo! wfien in use anwadapt ed'iwhem'tighten'ed to abutzwwailiof'saidav-shaped:

gmovevatz symmetrically-v disposed? points to forcea saicfifiaohsupponting shamc axiafly-intbwtight. flit 8;; ttonafin age entr-wititsaid omm Bowen-1cm m: sl'ianki ember: 3mm: too! suppnrsmgi' slianwtbgether iornnltary rotatiem KLBERW THDMXSF REFERENCES; GITEDz The ibfiowin'g referencesare of record in tha file ofitfiismatenmz um'mnaammsammms:

G'DHERLREFERENGES-I 

